Delay arming device



Aug. 10, 1948. J. F. MCCASLIN 2,446,545

DELAY ARMING DEVICE Filed April 17, 1945 2 Sheets-Sheet l James E M:Easlin e mwamw flmvwaqs 1948- J. F. McCASLIN 2,446,545

DELAY ARMING DEVICE Filed April 17, 1945 2 Sheets-Sheet 2 James F.MEEEIEHFI Patented Aug. 10, 1948 UNITED STATES ATENT OFFICE (Grantedunder the act of March 3, 1883, as amended April 30, 1928; 370 0. G.757) 2 Claims.

The invention described herein may be manufactored and used by or forthe Government for governmental purposes without the payment to me ofany royalty thereon.

This invention relates to a delay arming device forming a part of thebooster charge and which is interposed between the fuze and boostercharge to prevent a premature detonation of the booster charge throughan inadvertent premature functioning of the fuze; and also prevents aregenerative action which could change a low order detonation, caused byinitiation of the shell loading other than that caused by the fuze andbooster combination, to a high order through the low order beingsufficient to function the rotor detonator which in turn would. buildthe action up to a high order.

More particularly, it is an aim of the invention to provide acentrifugally actuated means including a rotor having a detonatorforming a part of a communicating flash passage between a fuse andbooster charge, which passage is normally in a non-registering positionand which is moved into a registering position by centrifugal f orceduring flight of a projectile containing the device.

Still another further object of the invention is to provide a novelregulating means for releasing the rotor, which includes an escapementfor regulating the time at which the rotor is released.

Still a further object of the invention is to provide a device of theabove described character especially intended for use in projectiles oflarge calibers which will not only render the projectile positively boresafie, but which can be regulated to prevent arming of the projectileuntil it has traveled a sufficient distance from the muzzle of theweapon, from which it is fired, to be beyond a position at which the guncrew could be endangered by detonation of the projectile; to therebyprevent injury to the gun crew due to tree bursts or the projectilestriking any mask during the initial stage of its flight.

Other objects and advantages of the invention will. hereinafter becomemore fully apparent from the. fol-lowing description of the drawings,which illustrate preferred embodiments of the invention, and whereinFigure. 1 is a horizontal sectional view, partly in plan, showing thedelayed arming device in a nonregi'stering or safe position;

Figure 2' is a view similar to Figure 1 showing the device inaregistering or armed position;

Figure 3 is a sectional view taken along the line 3--3 of Figure 1;

Figure 4 .is a sectional view taken along the line 4-4 of Figure 1, and

Figure 5 is a fragmentary view, similar to Figure 1, of a slightlymodified form of the device.

Referring more particularly to the drawings, wherein like referencecharacters designate like or corresponding parts throughout the severalviews, and referring particularly to Figures 1 to 4, 6 designatesgenerallya housing which is adapted to be interposed between a boostercharge and a fuze, not shown, and which is further adapted to functionas a coupling means between the fuze and booster charge. The housing 6includes a solid rear portion 1 which is provided with a forwardlyopening, circular cavity 8 and a recessed portion 9 which likewise opensforwardly, and a portion of which communicates with the cavity 8. Ashaft 50 is axially disposed in the cavity 8 and extends into a recess Hin the portion 1. Shaft it may be either fixed or journaled in therecess H and provides a support for a rotor l2 which is rotatablymounted in the cavity 8 and through which the shaft Hiextends. The shafti0 may be fixed to the rotor l2 or rotatably connected thereto,depending upon whether the shaft is fixed or rotatably mounted, in therecess H As clearly il-- lustrated in Figure I, the rotor I2 is recessedso that the preponderance of its weight is in one segment thereof andwithin said segment portion the rotor 12 is provided with a cavity orrecess 13'. The aforementioned segment of the rotor i2 is provided witha notch it which opens outwardly of the periphery thereof.Circumferentially spaced from the notch I 6, the rotor i2 is providedwith a bore I4 which extends therethrough, from end to end thereof, andwhich contains a detonator l5.

A sear l l, in the form of a lever, is disposed in a part of therecess 9and has one end thereof pivotally mounted on a pin i8 which extends intothe housing portion 7. The opposite, free end of the sear H is providedwith a radially projecting finger l9 which extends into the cavity 8 andinto the notch l6 for normally retaining the rotor 52 in its position,as seen in Figure 1. As seen in Figure 4, the recess portion 9-includesa substantially circular forwardly opening cavity 26 and a shaft 2fextends axially therethrough. and is journaled in a forwardly openingrecess 23 of the housing portion 1. A centrifugally actuated weighteddetent 22 is keyed to the shaft 21 and is rotatably mounted in thecavity 28. A disk 24, provided with teeth extendinga part of the waytherearound and forming a gear segment, is keyed to the outer or forwardend of the shaft 21 and is disposed in;

front of the detent 22 and to the front of the cavity 20 and within therecess 9. The free end portion of the sear H, as seen in Figure 4, isdisposed behind the gear segment 24 and partially in overlappingrelationship thereto for engagement with the detent 22 which functionsto retain the sear finger l9 in'engagement with the notch l6.

As seen in Figure 3, a shaft 25 journaled in the forwardly openingrecess 26 of the housing portion I and projects forwardly therefrom intothe recess 9 and is provided with an escapement wheel 2! which is keyedthereto and disposed in the recess 9. The escapement wheel 21 isdisposed be- 7 hind the gear segment 24 and in partially overlappingrelationship thereto, and a pinion 28 is keyed to the forward end of theshaft 25 and is disposed to mesh with the teeth of the gear segment 24.An escapement pallet or verge 29 is keyed to one end of a shaft 30 whichis journaled in a forwardly opening recess 3|, of the housing portion 1,and said escapement 29 is likewise disposed in the recess portion 9.Escapement 29 is in the same plane as the escapement wheel 21 and ispositioned adjacent thereto so that pawls 32 and 33 thereof alternatelyengage the teeth of the escapement wheel 21 and by a camming actriontherewith, in a conventional manner, permit a regulated step by stepmovement of the escapement wheel 21, pinion 28 and the gear segment 24,when said segment teeth are enmeshed with the pinion 28. A setback pin34 is reciprocally mounted in a restricted portion 35 of a bore 36,

which is formed in the housing portion 1 and has an inner end whichextends into the bore 36 and to which is secured a collar 37. Anexpansion spring 38 is contained in the bore 3'6 and bears againstcollar 31 for urging the pin 34 forwardly and toward the escapementwheel 21. Escapement wheel 2'! is provided with an opening 39 to receivethe pin 34 which functions, when in its normal position, as seen inFigures 1 and 3, to prevent movement of the gear segment 24, escapementwheel 21 and the parts connected thereto.

The cavity 8 is provided with a fixed pin 40 which is disposed thereinand within a recessed portion of the rotor 12 to engage the rotor, uponrotation, to limit the rotational movement thereof.

As clearly illustrated in Figures 1 and 2, all of the parts previouslydescribed and contained within the housing 6 are located so as to beresponsive to the centrifugal force produced by the rotation of thehousing 6 when contained in a projectile, while in flight.

Assuming the parts to be in the positions, as seen in Figure 1, andfurther assuming the housing 6 to be connected to a fuze and booster anddisposed in a projectile, not shown, upon said projectile being firedfrom a weapon, pin 34 will be set back by inertia against the force ofits spring 38 and will thereby move out of engagement with the opening39 to release the escapement wheel 21. Pin 34 is preferably locked outof engagement with wheel 2! by means of its inability to again find itsway into the restricted portion of 35 of bore 36. The rotation of thehousing 6, by the projectile in flight, will cause a centrifugal forceto be applied to the combined driving arm and detent 22 which willthereby be swung in a counterclockwise direction, as seen in Figure 1.The counterclockwise swinging movement of the detent 22 will beregulated by the escapement 21, 29 due to the fact that the detent -2-2and gear segment 24 are both keyed to the shaft 2| and the pinion 28which is in mesh with gear segment 24 is keyed to escapement wheel 21.Thus, the speed at which the detent 22 is swung outwardly will begoverned. A the arcuately shaped extension 4| of the detent 22approaches its position of Figure 2 the teeth of gear segment 24 willmove out of engagement with pinion 28 allowing the weighted detent 22 tomove freely thereafter, to thus insure that detent 22 will move out ofengagement with the free end of the sear IT, to thereby release the searto permit it to be swung outwardly by centrifugal force, from itposition of Figure 1, to its position of Figure 3. This outward movementof the sear I I will cause the sear finger I9 to move out of engagementwith the notch 16 and permit the rotor I2 to be moved by centrifugalforce in a counterclockwise direction, from its position of Figure 1 toits position of Figure 2. The rotor l2, in its position of Fi ure 3,is-disposed so that the flash passage l4, containing the detonator I5,is registering with aligned passages, not shown, of the booster and fuzethrough which a flash from an explosive charge or train in .the fuse,not shown, is adapted to be conveyed to the booster by ignition of thedetonator 15, which thus forms a part of the explosive train. It willthus be readily apparent that the release of the rotor l2 and itsmovement to its position of Figure 2 will arm the booster arming device,comprising the invention, to enable the fuze and booster, with which itis associated, to function when the fuze is set off. Further, it will bereadily apparent that prior to the time that the sear I1 is releasedfrom the rotor l2 and moves to its position of Figure 2, the device willprevent detonation of the booster charge should the fuze be prematurelyset off. due to the fact that the flash from the fuze would then betrapped in the blind cavity l3 and be rendered harmless thereby.

It will be noted that when the rotor I2 is in its armed position ofFigure 2, the preponderance of its weight is still so disposed that saidrotor is under a stress exerted by centrifugal force and is held fromfurther swinging movement by engagement of a portion thereof with stop40, so that the rotor is held effectively in an armed position bycentrifugal force. Obviously, if desired, a conventional spring latchcould be provided for positively latching the rotor in its armedposition. It will also be readily apparent that when pin 34 is set backby acceleration, the escapement wheel will begin its rotational movementto thereby move the opening 39 out of alignment with pin 34. The detent22 will complete the swinging movement to release the sear I! after thetime factor governing the opening point has been passed.

A slightly modified form of the invention is dis closed in Figure 5 andwhich differs from the device as shown in Figures 1 to 4 only in thatthe sear I! is set further to the front and in front of and partiallyoverlapping the gear segment 24. A separat detent 42 is keyed to theshaft 2|, and disposed in front of the gear segment 24 and in the sameplane as the sear IT, to engage the free end of the sear for holding itsfinger I 9 in engagement with the notch I6. The shape of the detent 42corresponds to the shape of the weighted detent 22, as clearlyillustrated in dotted lines in Figures 1 and 2 and is utilized inaddition thereto.

As the functioning of the parts shown in Figure 5 are the same as thoseshown in Figures 1 to 4, a further description of the modification isconsidered unnecessary.

Various other modifications and changes are likewise contemplated andmay obviously be resorted to without departing from the spirit and scopeof the invention as hereinafter defined by the appended claims.

I claim:

1. A delay arming booster for a projectile of the type which rotatesduring flight comprising a booster housing interposed between a fuze andits booster charge, said housing having a circular, off center cavityand an off center recess in the same plane with said cavity andcommunicating therewith; a rotor turnably mounted in said cavity about arotor shaft, said rotor being eccentrioally weighted for rotation aboutits shaft by centrifugal force upon projectile rotation; a flash passagein said booster housing; a flash hole in said rotor initially out ofline with said flash passage to block same; a notch in the periphery ofsaid rotor; a sear eccentrically pivotally mounted in said recess forrotation by centrifugal force from an initial safety position into anarmed position; a finger on said sear engaging said rotor notch tomaintain said rotor in its initial position; an eccentrically weightedpivotally mounted detent in said recess arranged to initially maintainsaid sear in the safety engaged position, but rotatable by centrifugalforce upon projectile rotation to release said sear; a gear train andescapement mechanism energized by rotation of said detent to delayrotation of same; a stop for said rotor to position same with said flashhole aligned with said flash passage upon disengagement of said searfinger from said peripheral notch.

2. The invention recited in claim 1, including a set-back actuatedrelease for said escapement mechanism arranged to normally blockmovement of same.

JAMES F. McCASLIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number

